Composition containing benzimidazole derivatives for softening rinse

ABSTRACT

Surface-active benzimidazole derivatives able to exist in either cationic or zwitterionic form and useful as textile treating agents are disclosed. The compounds are effective as textile softening agents substantive to fabrics as the ordinary pH of fabric rinsing operations and removable from fabrics in a zwitterionic form under succeeding alkaline washing conditions.

United States Patent Atkinson Dec. 24, 1974 COMPOSITION CONTAINING [58Field of Search 25218.8, 8.75, 110, 117, BENZIMIDAZOLE DERIVATIVES FOR252/524, 528, 542, 547; 117/47, 139.5 SOFTENING RINSE [56] R f C d eerences lie [75] Inventor #53213 3; g gfi UNITED STATES PATENTS3,555,040 l/l971 Frick et all 252/8.8 X [73] Asslgneei El P tF aCompany, 3,673,209 6/1972 Frick et a]. t. 252/8.8 X

incinna 1, 10 22 Filed; May 1 1973 Primary Examiner-Stephen J. Lechert,Jr.

Attorney, Agent, or Firm-Forrest L. Collins; Thomas pp No.1 361,740 H.Flaherty; Richard c. Witte Related U.S. Application Data 57 ABSTRACT[62] Division Of Ser. NO. 230,032, Feb. 28, 1972, 1

abandoned, Surface-active benzimidazole derivatives able to must ineither cationic Or zwitterionic form and useful as F i Application p i iData textile treating agents are disclosed. The cOmp unds Mar 1971 GreatBritain 6699, are effective as textile softening agents substantive tofabrics as the Ordinary pH Of fabric rinsing Operations [52] Us Cl252/88 252/8 252/ and removable from fabrics in a zwitterionic form252/5'28 252/547 under succeeding alkaline washing conditions. [51] Int.Cl D06m 13/46 7 Claims, N0 Drawings COMPOSITION CONTAINING BENZIMIDAZOLEDERIVATIVES FOR SOFTENING RINSE This is a division of application Ser.No. 230,032, filed Feb. 28, 1972, now abandoned.

This invention relates to certain benzimidazole derivatives useful astextile treatment agents and able to exist in either cationic orzwitterionic form.

Quaternary ammonium compounds having at least one long chain (about Cupwards) hydrophobic radical in the molecule have long been known. Theyare useful as cationic surface active agents (so called. invert soaps"),as textile softening agents and as bactericides. When intended for useas surface active agents, the long chain group usually has about 12 tocarbon atoms. When intended for use as textile softeners, long chaincompounds, for instance having about 16 to 22 or more carbon atoms, arepreferred, especially compounds with two long chain groups. Typicalexamples include dodecyldimethyl benzyl ammonium chloride,dodecyltrimethyl ammonium chloride, distearyl climethyl ammoniumchloride, the corresponding bromides, and many others of similarstructure.

These compounds, particularly distearyl dimethyl ammonium chloride, havebeen used commercially in textile softening compositions intended to beadded to the last rinse water after a conventional washing process, andattempts have been made to use them in detergent compositions intendedto be combined washing and textile softening agents.

Being cationic, these substances ordinarily react with anionicdetergents to form insoluble substances, and so their use in thepresence of anionic detergents is not normally practicable. Furthermore,they have a strong affinity for fabrics, especially cotton and wools, afact which plays an important part in their effectiveness as textilesofteners, but also has the effect that they generally are notcompletely washed out of the fabric in a succeeding wash. They thereforetend to build up on repeatedly washed fabrics, where they may impair there-wetting properties of the fabrics, and where they tend to causediscoloration, an unpleasing greasy feel, fiber snagging and evenundesirable odors.

Other quaternary ammonium compounds constitute the known zwitterionicsurface-active compounds, such as long chain carboxylic betaines,sulphobetaines, sulphato-betaines and sulphito-betaines. These compoundsare valuable wetting agents and detergents. Being internal salts, theydo not react with the metal ions present in hard water, especiallycalcium ions, and thus are almost unaffected by water hardness. For thesame reason, they are compatible with anionic, cationic and nonionicdetergents. Their affinity for and wetting effect upon certain highlyhydrophobic fibers, such as polyamine and polyester fibers, renders themparticularly valuable for removing certain types of soils, especiallygreasy soils, from these materials. They are also remarkably effectivein cleaning cotton fabrics soiled with dirt which contains clayparticles. However, they are not strongly substantive to fabrics and arenot very effective textile softening agents. These known betaine andbetaine-like compounds exist in zwitterionic form over a wide range ofpH. In relatively strongly acid conditions they do become cationic, butthe necessary acidity is outside the practical range for washing fabricsor the person.

The present invention is based on the discovery of a new class ofdetergents which are cationic under weakly acid conditions, and are:zwitterionic under weakly alkaline conditions, relative to their pKavalue as defined hereinafter. Thus, if present at the ordinary pH of arinsing operation in an aqueous solution (which need not, of course,necessarily in fact constitute the rinse after a wash) they are largelyin cationic form and are effective as textile softening agentssubstantive to fabrics. In the ordinarily alkaline conditions of a subsequent conventional washing operation, they convert to a zwitterionicform and, thus, are at least partially removed from the fabrics. When soremoved, they are compatible with the detergent composition and may evenenhance its effectiveness. Furthermore, the adsorbed cationic and/orzwitterionic layer on the textile fibers provides a surface which tendsto repel important classes of soil and to promote their separation fromthe surface and their dispersion in a subsequent alkaline wash when theadsorbed layer is rendered nonsubstantive. Thus, these substances canact as soil release agents which are at least partly removed at eachwash and can be re-applied before the surface is reexposed to soiling,as more fully described hereinafter. They may also provide antistaticproperties for the surfaces treated with them.

SUMMARY OF THE INVENTION or its corresponding zwitterionic form whereineither (i) R, is an alkyl group having from 14 to 22 carbon atoms or analkylphenyl or alkylbenzyl group having from eight to 16 carbon atoms inthe alkyl chain, and R is alkyl of from one to 16 carbon atoms or agroup (C H O),,,H where m is from one to 20; or (ii) each of R and R isan alkyl group of from 10 to 22 carbon atoms or an alkylphenyl oralkylbenzyl group as defined above; R is alkyl of from one to six carbonatoms or a group (C I-I O),,,H where m is from one to 20; n is aninteger from 1 to 4; and X is an anion.

In its composition aspect, the present invention provides textilesoftening compositions containing the benzimidazole derivatives andsuited to use as presoaking or rinse-added compositions. Also providedare detergent compositions containing the benzimidazole derivativesherein and adapted to use as cleaning and softening compositions.

In its method aspect, the present invention provides a method oftreating fabric materials whereby the fabrics are improved in softnesswithout undesirable buildup with succeeding washing treatmentscomprising the steps of treating the fabrics with a solution of acationic compound described hereinbefore thereby to improve softnessand, thereafter, washing the fabrics under alkaline conditions therebyto remove the softener in a zwitterionic form. Also provided is a methodwhereby fabrics can be similtaneously cleaned and softened.

DETAILED DESCRIPTION OF THE INVENTION As is apparent from thehereinbefore defined formulae, one or two long chain lipophilic groupsare attached to the quaternary nitrogen atom. If only one is present, itcan be an alkyl group of from 14 to 22, and preferably from 16 to 20,carbon atoms, or an alkylphenyl or alkylbenzyl group having from eightto 16, preferably to 14, carbon atoms in the alkyl chain. If two arepresent and each independently can be an alkyl group of from 10 to 22,preferably 12 to 18, carbon atoms or an alkylphenyl or alkylbenzyl groupas above. The latter group can be derived from a typical detergentalkylate. The one or two short-chain groups, R and R;,, can beshort-chain alkyl groups, having from one to six carbon atoms;preferably, R and R are methyl or ethyl. The short-chain groups can alsobe the corresponding hydroxyalkyl groups, e.g., hydroxyethyl, orhydroxyalkyl groups can be ethoxylated, for instance with l to ethyleneoxide residues. In the hereinbefore defined formulae, the number nrepresents the number of methylene groups and is an integer of from I to4; preferably n is from 1 to 3 and especially 1.

The anion X may be any water-soluble anion which is convenient. The mostusual anions, especially in detergent, softening and like compositions,are halides, especially chloride or bromide, sulphate or methosulphate.Some others suitable, generally for other purposes, include bisulphate,nitrate, perchlorate, and fluoroborate.

Preferred compounds according to the invention are those which have apKa value in the range from 5 to 10, especially in the range from 8 to10. The optimum pKa value will depend to some extent upon the intendedapplication. The pKa of a weak acid, such as the present compounds, inaqueous solution is defined as the pH of the solution when the compoundis half neutralized, i.e., in the present instance, when it is 50 molarpercent in zwitterionic form and 50 molar percent in cationic form. AtpH values near to the pKa value both forms are present to a considerabledegree.

The benzimidazole derivatives can be conveniently synthesized. Forexample, a 2-haloalkyl benzimidazole having the formula where X ischloro or bromo and n is an integer of from 1 to 4 can be prepared bythe reaction of ophenylenediamine and a haloalkanoic acid. Thepreparation of 2-chloromethylbenzimidazole from2-hydroxymethylbenzimidazole and thionyl chloride is disclosed byHofmann in Imidazole and its Derivatives, Interscience Publishers, Inc.,New York, Part I, pp. 303-304 (1953). The 2-haloalkyl benzimidazole,prepared in the manner described above, can be reacted with a tertiaryamine having the formula NR R R where R R and R are defined ashereinbefore mentioned. The preparation of 2-monoalkyl andZ-dialkylaminomethylbenzimidazoles by reaction of 2-chloromethylbenzimidazole with amines is disclosed by Hofmann, supra, atpage 31 l.

Ordinarily, the compounds of the invention are applied to fabrics froman aqueous solution, and conveniently at some atage in a washingprocess. They have surprisingly been found to have valuable textilesoftening properties when incorporated at any stage of a washingprocess. Thus they can be added, as are most conventional textilesoftening agents, at the rinse after a washing process. Provided thatthe rinse liquor has a pH in a range such that they are to aconsiderable degree in cationic form, they are substantive to mostfabrics and are effective softeners.

Alternatively, the compounds can form part of the active detergentcomponent of a washing composition formulated so that they arepredominantly in zwitterionic form during the washing step. Theproportion of the compound still present in the rinse liquor, whendilution with tap water or the like has reduced the alkalinity, is thenavailable in cationic form to act as a substantive fabric softener.

The invention also provides textile treatment agents containing thequaternary ammonium benzimidazole in admixture with a diluent. Thenature of the diluent will of course depend on the particular type oftextile treatment agent. For example, a detergent composition willcontain a detergent ingredient.

Suitable proportions of the benzimidazole in a detergent compositiondepend upon the nature of the composition. In most conventional heavyduty detergent compositions, a content of benzimidazole of l to l0percent by weight, especially about 5 percent, gives good results.

A particularly effective method of employing these compounds as textilesoftening agents is to give fabrics which are to be washed a preliminarysoaking or wetting in an aqueous solution of the cationic form of thecompound. Thereafter, a detergent composition, such as a typical builtheavy duty detergent composition, can be added to the same solution andwashing and rinsing carried out normally. Alternatively, surplussolution can be separated from the fabrics, for instance by spin drying,and then they can be washed and rinsed in the ordinary way. Generallythe former alternative is preferred.

In both these latter methods of applying the benzimidazole derivativesof the invention, it might be expected that the amount of adsorbedderivative would build up in repeated treatments, somewhat as in thecase of the prior art cationic textile softeners, but it is surprisinglyfound that this does not occur. The reason for this is not known,although it may be postulated that the washing process always removessome of the entrapped, but non-substantive, zwitterionic form of thebenzimidazole derivative, so that the amount remaining reaches a mazimumlevel after one or a few treatments and thereafter does not increase.

It is preferred that there should be from about 0.01 to 0.5 percent,especially about 0.1 percent of the cationic form of the benzimidazolederivatives, by dry weight of the fabric, present in the treatmentsolutions containing said cationic form, i.e., in presoak or rinsesolutions.

The agents intended for use as rinse additives preferably contain pHbuffers, of a type and in amount such that an aqueous solution of theagent (of concentration such that it contains 0.1 percent by weight ofthe benzimidazole) has a pH less than the pKa value of thebenzimidazole, more preferably at least 2 units below the pKa value. Ifthe pH approaches the pKa value, it is advisable to have a further,preferably nonionic, surfactant present to solubilize that part of thebenzimidazole derivative which is in zwitterionic form. Suitablebuffering agents are known in the art, for example phosphates,carbonates, borates, citrates and tartrates and the corresponding acids.The content ofthese components in the rinse additive compositionsdepends upon how they are intended to be employed. Effective andconvenient compositions contain from about 1 to percent by weight, forexample about 5 percent, of the cationic form of the benzimidazolederivative, and can be used at a concentration of about 0.2 to0.5percent, by weight, in a rinsing or post-wash soaking solution, butthese figures are not to be considered limiting. When benzimidazolederivatives of the invention are employed which are poorly soluble inwater even in their cationic form, they can be solubilized by includinganother surface active agent, preferably a nonionic agent, in thecomposition.

Detergent compositions containing the benzimidazole derivatives includebuilt detergent compositions, and can contain any detergency builder,such as the water-soluble (usually sodium or potassium) phosphates andpolyphosphates, carboxylates, silicates, borates, etc., and chelatingagents such as nitiloctriacetates, polycarboxylates such as thosedescribed in US. Pat. No. 3,308,067 (Mar. 7, 1967), citrates andgluconates. Neutral salts such as alkali metal sulphates and chlorides,and bleaching agents such as sodium perborate, percarbonates orperphosphates can also be present. The organic surfactant component cancomprise anionic, nonionic or zwitterionic surfactants. Preferably, themajor part of the surfactant component is anionic. Suitable surfactantsare known in the art. Suitable anionic surfactants include the sulphonicand sulphuric acid derivatives, such as alkyl aryl sulphonates, alkylsulphates and alkyl ether sulphates, the nonionic surfactants includethe sulphonic and sulphuric acid derivatives, such as alkyl arylsulphonates, alkyl sulphates and alkyl ether sulphates; the nonionicsurfactants include polyethoxyalcohols, polyethoxy -alkyl phenols,polyethoxy -fatty acids, polyethoxy-amines, polyethoxy polypropylenoxycondensates, polyethoxy sorbitan esters and many others, and can includetertiary amine oxides and phosphine oxides; zwitterionic surfactantsinclude quaternary ammonium carboxylates (betaines) and sulphonates(sulphobetaines) and the like, some of which have been mentioned above.Examples of suitable detergents are provided in US. Pat. No. 3,213,030,issued Oct. 19, 1965, lines 53-75 of col. 3 lines 1 to 75 of col. 4 andlines 1 to 30 of col. 5, which disclosure is incorporated herein byreference. Nor mally, the built detergent compositions of the inventionwill comprise the benzimidazole of the invention and an admixture ofdetergent active and builder salt as described above in a ratio ofdetergent to builder of from about 2:1 to about 1:10 by weight.

Agents intended for use as pre-soak additives, i.e., for soaking fabricsbefore they are washed, can consist solely of the cationic form, forinstance the hydrochloride, of the benzimidazole derivative, butpreferably they contain a diluent which can be or include a component tomake them convenient to handle or aesthetically attractive. Whenbenzimidazole derivates which are poorly soluble in water even thecationic form, for instance some of those wherein both R, and R arehydrophobic groups, are used, they can be solubilized by includinganother surface active agent, for instance a nonionic, in thecomposition.

The agents of the invention can of course contain as appropriate in eachcase, the usual minor components such as suds controlling agents,bleaching agents, bactericides, enzymes and activators or stabilizerstherefore, dust inhibitors, soil suspending agents, tarnish or corrosioninhibitors, opacifiers, dyes, perfume and the like.

The following Examples illustrate the invention:

EXAMPLE ll PREPARATION OF DlMETHYL-HEXADIECYLQ BENZIMIDAZOLYLMETHYL)AMMONIUM CHLORIDE.

Five grams l-chloromethylbenzimidazole (0.03 mole) and 8.1 gramsdimethylhexadecylamine (0.03 mole) in acetone ml) were heated underreflux (1 hour) and allowed to cool. The product (11.1 g.) was removedby filtration and had a melting point of 9395C. This was converted tothe relatively insoluble zwitterionic form upon basification (meltingpoint, l31-l34C.)

The corresponding n-dimethyl docosyl compound (melting point, 5055C.;zwitterion, l9l-l93C.) was prepared using the procedure of Example 1above but employing dimethyldocosylamine in place ofdimethylhexadecylamine.

EXAMPLE 11 Solutions were prepared consisting of a. water acidified topH 4.

b. 1 percent by weight solution of the compound hav ing the structure:

in water, and acidified to pH 4. This compound has a pKa value in therange 8.5 to 9.5.

Test pieces of cotton Terry Towelling were dipped in the solutions (atabout 20C) rinsed in water of pH about 4 and dried.

The test pieces treated in solution (b) had softer feel than thosetreated in solution (a).

Some of the test pieces from solution (b) were stirred in water (atabout 20C) rendered alkaline, to pH 10. The solution became visiblycloudy as the poorly soluble and non-substantive zwitterionic form of Bbecame detached from the fabric.

Other test pieces which has been treated in each solution (a) and (b),were soiled with a mixture of motor engine oil and soot. They werestirred in aqueous alkaline solutions as above, and it could be clearlyseen that more soil was transferred into the solution from the testpieces treated in solution (b) than from the others, and correspondinglythe test pieces were visibly cleaner.

A similar result was observed when the soiled treated test pieces werewashed at 60C in a 0.5 percent by weight solution of a typicalconventional heavy duty built detergent, having pH in this solution ofabout 10.

EXAMPLE III A composition was prepared consisting of parts of thecompound and 95 parts of a commercial granular built detergentcomposition comprising as essential components:

9.3 percent mixed dodecylbenzene sulphonate and tallow alkyl sulphate,

2.5 percent soap,

36 percent sodium tripolyphosphate,

7 percent sodium silicate,

8 percent sodium sulphate,

25 percent sodium perborate tetrahydrate,

7 percent moisture, with minor components including enzymes, sudsstabilizer, optical brightener, perfume and the like constituting thebalance.

Test pieces of cotton terry towelling and cotton towelling were washedin a 0.5 percent by weight solution of this composition in tap water(hardness 170 ppm as CaCo at 50C for 5 minutes, and rinsed thoroughlyand dried. Corresponding test pieces were washed similarly in a 0.5percent by weight solution of said detergent composition without thebenzimidazole derivative.

In each case 60 g of fabric were treated in 1 liter of detergentsolution, corresponding to 0.4 percent of benzimidazole derivative byweight of the fabric.

The treatment was carried out 5 times and the fabrics were then comparedby a panel of six judges, blindfolded to avoid any confusion resultingfrom visual impression. All six judges found the fabrics treated withthe composition ofthe invention softer than the control fabrics.

EXAMPLE IV 0.25 g of the benzimidazole derivative of Example III weredissolved in 1 liter of tap water at 50C, and 60 g of test fabrics,similar to those treated in Example III, were soaked for 2 to 5 minutesin this solution. Then there were added to the solution 5 g of thedetergent composition of Example III, and the fabrics were washed for 5minutes, and rinsed and dried normally. They were compared as in ExampleIII with fabrics washed similarly, but employing only water for thepresoak. After only one such treatment the judges all found the fabricspretreated in the solution of benzimidazole softer than the controlfabrics.

EXAMPLE V Test fabrics were washed with the detergent composition aloneas in Example III and rinsed once.

They were then given a second rinse in 1 liter of a. tap water, or b. asolution containing 250 parts per million of the benzimidazolederivative of Example III, or c. a solution as (b) but also containingan equal weight of a mixture of 2 parts sodium citrate and 3 partscitric acid to adjust the pH to 5. The fabrics were then spin dried anddried fully. After only one treatment the fabrics rinsed in solu tions(b) and (c) were adjudged softer than those rinsed in water only.

EXAMPLE VI Similar results were obtained in the treatments of ExamplesIV and V when the benzimidazole derivative was replaced by one havingthe formula:

together with twice its weight of a nonionic surfactant, viz., coconutfatty alcohol condensed with six molar proportions of ethylene oxide. Inthe absence of the nonionic surfactant, some softening effect wasobserved with the latter compound, but less than that with the othercompounds alone, or with the said mixture.

EXAMPLE VII Test pieces of cotton shirt fabric were treated as inExample V(b). By comparison similar test pieces were given their secondrinse in a solution containing 250 parts per million ofditallowyldimethyl ammonium chloride, added in the form of a commercialfabric softener composition.

After one cycle the pieces rinsed with the benzimidazole derivative werejudged slightly softer than those rinsed in the conventional softener.After 3-6 cycles there was no consistent difference, after 9 and I2cycles the pieces rinsed in the conventional softener were adjudgedsofter. However, they had a more greasy" feel and had become morediscolored than the pieces rinsed in the benzimidazole composition.

EXAMPLE VIII Example IV was repeated using 240 g of test fabrics,corresponding to 0.1 percent of benzimidazole derivative by dry weightof fabric. After one such treatment the judges all found the fabricspretreated in the solution of benzimidazole derivative softer than thecontrol fabrics.

What is claimed is:

l. A textile softening rinse composition consisting essentially of aquaternary ammonium benzimidazole derivative having the formula:

wherein either (i) R is an alkyl group of from 14 to 22 carbon atoms oran alkylphenyl or alkylbenzyl group of from eight to 16 carbon atoms inthe alkyl chain, and R is alkyl of from one to six carbon atoms or agroup (C H O),,,I-I where m is from one to 20; or (ii) each of R and Ris an alkyl of from l0 to 22 carbon atoms or an alkylphenyl oralkylbenzyl group as defined above;

R is an alkyl of from one to six carbon atoms or a group (C H O)m wherem is from 1 to 20;

n is from 1 to 4; and

X is an anion and a pH buffering agent selected from the groupconsisting of water-soluble phosphates, carbonates, borates, citrates,tartrates and the corresponding acids thereof, the pH of a solution ofthe composition having 0.1 percent by weight of the benzimidazolederivative being below the pKa value of the benzimidazole derivativesuch that the benzimidazole derivative is in its cationic form.

2. The composition of claim 1 wherein the said pH is at least 2 unitsbelow the said pKa value, said pKa value being defined as the pH of thesolution when the compound is 50 molar percent in zwitterionic form and50 molar percent in cationic form.

3. A textile softening and detergent composition comprising awater-soluble non-cationic surface-active agent; a water-solublealkaline detergency builder compound; and a benzimidazole derivative ofclaim 1.

4. The composition of claim 3 wherein the benzimidazole derivativecomprises from 1 to 10 percent by weight of the composition.

5. The composition of claim 4 wherein the surfaceactive agent to buildersalt is from 2:1 to 1:10.

6. Composition of claim 1 wherein said quaternary ammonium benzimidazolederivative is present in an amount sufficient to provide from about 0.01to 0.5 percent by dry weight of the fabric being treated.

7. The composition of claim 1 wherein the quaternary ammoniumcomposition is dimethyl-hexadecyl- (2-benzimidazoly-methyl) ammoniumchloride.

1. A TEXTILE SOFTENING RINSE COMPOSITION CONSISTING ESSENTIALLY OF AQUATERNARY AMMONIUM BENZIMIDAZOLE DERIVATIVE HAVING THE FORMULA:
 2. Thecomposition of claim 1 wherein the said pH is at least 2 units below thesaid pKa value, said pKa value being defined as the pH of the solutionwhen the compound is 50 molar percent in zwitterionic form and 50 molarpercent in cationic form.
 3. A textile softening and detergentcomposition comprising a water-soluble non-cationic surface-activeagent; a water-soluble alkaline detergency builder compound; and abenzimidazole derivative of claim
 1. 4. The composition of claim 3wherein the benzimidazole derivative comprises from 1 to 10 percent byweight of the composition.
 5. The composition of claim 4 wherein thesurface-active agent to builder salt is from 2:1 to 1:10.
 6. Compositionof claim 1 wherein said quaternary ammonium benzimidazole derivative ispresent in an amount sufficient to provide from about 0.01 to 0.5percent by dry weight of the fabric being treated.
 7. The composition ofclaim 1 wherein the quaternary ammonium composition isdimethyl-hexadecyl-(2-benzimidazoly-methyl) ammonium chloride.